以马蹄莲为主体植物的人工湿地处理低浓度污水中试研究

Treatment of low concentration of wastewater using constructed wetland dominated by Zantedeschia aethiopica

人工湿地中集污染物吸收效果好、生境改善、观赏性好和经济性好于一体的植物筛选将支持湿地的长效低耗运行。报道了以观赏性和经济性植物马蹄莲(Zantedeschia aethiopica)为主要植物的人工湿地中试床(5 m×1 m×1.1 m)处理低浓度农村污水的研究。结果表明,在水力负荷为6,10和20 cm.d-1的条件下,该系统对CODCr(化学需氧量)、TN(总氮)、硝氮、氨氮和TP(总磷)的去除率分别大于56.4%、71.4%、71.4%、49.6%和56.6%。同处旺盛生长期(8月)而温度相近时,低水力负荷(6 cm.d-1)组的硝氮、氨氮和TP的去除率高;高水力负荷(20 cm.d-1)组的TN去除率高,进水TN中的有机氮占的比例比低水力负荷(6 cm.d-1)的高10%。马蹄莲人工湿地系统在休眠期(6月和7月)和在旺盛生长期相比,由于温度高而具有高的CODCr和N去除率,由于枯枝落叶的腐烂溶出以及进水负荷高而具有低的TP去除率。研究结果可为人工湿地等生态系统中选择植物时参考。

In wetland the selection of hydrophyte with better pollutant absorption, habitat enhancement, sound landscape and good economy is significant. Because this kind of hydrophyte will beneficial for the long-effective and low cost operation of the constructed wetland. Constructed wetland pilot system （5 m× 1 m× 1. 1 m）, with dominant helophyte of Zantedeschia aethiopica, one kind of fancy and economical helophyte, for low concentration agricultural wastewater treatment is reported here. The result showed that under the hydraulic load of 6, 10 and 20 cm·d^-1, the reduction rates on CODcr （chemical oxygen demand）, TN （total nitrogen）, nitrate, ammonia and TP （total phosphorus） are larger than 56.4%, 71.4%, 71.4%, 49.6% and 56.6%, respectively. Under the similar temperature and vigorous growth period （August）, the low hydraulic load set （6 cm·d^-1） has high nitrate, ammonia and TP removal rate, while high hydraulic load set （20 cm·d^-1） has high TN removal rate. The ratio of organic nitrogen to TN in the influent of high hydraulic load set （20 cm·d^-1） is 10% higher than low hydraulic load set （6 cm·d^-1）. Zantedeschia aethiopica constructed wetland system has high CODcr and N removal rate in dominant period （June and July） than in vigorous period, caused by the high temperature in dominant period. Low TP removal rate in dominant period than in vigorous period caused by the following reasons, first the decay of litter in the dominant period is obvious, and the high inflow rate in the dominant period. These results will bring reference for the hydrophytes selection in ecosystems such as constructed wetland.